Organic-inorganic Hybrid Coatings va Sol-gel Route for Leather Finishing

Abstract

Despite its popularity in other industries, including textiles, for the preparation of inorganic and hybrid coatings, the use of sol-gel for leather finishing is a barely explored field. To exploit its unique and versatile chemistry, we have here evaluated the potential of sol-gel route for preparing protective coatings and achieve, at the same time, water- repellency on treated leather. To this aim, tetra-ethyl-ortho-silicate (TEOS) and functionalized Si-alkoxides, containing either alkyl or fluorinated groups were selected and compared. The results of characterization indicate that, for the chosen formulations, alcohol-based sols were patently more effective than their water-based counterparts. Very high contact-angles were obtained for both alkyl- and fluorinated alkoxides, but, not surprisingly, fluorinated coatings provided a longer-lasting hydro-repellency. Sols well preserved leather grain, with no patent accumulation on pores or ridges, while only minor changes in color was observed in most formulations. Overall, our results suggest that a careful optimization of solgel formulation can offer unexplored, versatile and very effective solutions in leather finishing.